19/04/2019
V2.0
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Warning: The greatest threat for the engine is when it is working on too
lean mixture. This leads to rapid temperature growth of the piston crown, and
could result in melting or burning of the piston crown. In such case, serious
damages of cylinder, piston and crankshaft bearing could appear. In practice, it
means very high repair costs. Due to the fact that only the user is responsible
for mixture composition, the producer takes no responsibility for damages
caused by overloading the engine thermally, engine seizure, tearing off the
connecting rod, jamming the piston rings, using inadequate oil, or using a not
correct amount of oil!
Spark plug evaluation in the engine working previously for a long time at idle speed is
not reliable. For proper evaluation you should turn the engine off after a few minutes on
medium and high speed (horizontal flight) and land on the turned-off engine.
Second stage: If the spark plug has dark color or is black after the test flight, we can
continue flying also using maximum engine power.
Attention: Evaluating the state of the spark plug is the only one way of
checking whether the mixture’s composition is correct!
